1. Field of the Invention
The present invention relates to a data backup technique in a system composed of a plurality of information processing machines (apparatuses), and in particular it relates to a data backup system (preservation of data) and a data restore system (recovery of data) for a plurality of client machines (apparatuses) in a network system and a method thereof.
2. Description of the Prior Art
The reduction of TCO (total cost of ownership) is a subject in the field of a network/system management, and the management cost of the client machines hinders the reduction of TCO.
The recovery from a disk-crush needs a lot of manpower for the re-installment and environmental setting of an OS or application soft. The cost for recovery is regarded to be the main cause of raising the management cost.
In order to cope with the recovery from a disk-crush, it has been known that to have a backup is an effective way, and concerning the backup technique in the network system, for example, a backup technique is described in a Japanese Patent Laid-open No. Hei 2-297643. The purpose of the technique is to obtain backup for a plurality of client machines (work station), and a server to be used for backup is provided in this technique and backup files on the client machines are stored in the server.
According to the above technique, the size of data backup area on the server is the total sum of the backup data of all client machines (work station), so that when the number of client machines is large, a backup area on the server is necessary to be made large correspondingly thereto. Considering the disk capacity necessary for backup, if the backup only for the server is performed and that for the client machines is given up, as an outgrowth of such an idea the recovery from a disk-crush becomes impossible.
An object of the present invention is to reduce the backup data size of a storage unit of client machines in the environment where a plurality of client machines are used, and further object of the present invention is to expedite backup by removing obstacles for backup and to enable the system to cope with the recovery from a disk-crush. A still further object of the present invention is to reduce the management cost of the system.
In order to achieve the above-mentioned objects, the present invention provides a data backup system executed by an information processing system including a plurality of client machines and at least one unit of server and a method of operation thereof. The data backup system detects data common to respective client machines and data unique to the respective client machines, and stores the common data portion and the unique data portion separately.
In the present invention, common portions in the data (file groups) of respective client machines are detected and the common portions and the unique portions are stored (backup) separately, so that the total capacity of backup data can be reduced.
In many cases, a file or a file group of each client unit in the same network system has a similar configuration and contents. As a result, the contents of the backup data of each client unit are apt to be similar ones to each other. The present invention utilizes this characteristic.
In other words, in the case of a backup data storage means composed of a group of data or a plurality of groups of data in the equipment having a storage means, the contents of data contained in the backup data in the different client machines are compared, and when the identical contents are found in the different machines, the groups of data having the identical contents in the different machines are summarized to a group of data and stored.
Further, the present invention comprises a storage means for storing the common backup data forming a group of data or a plurality of groups of data for the above-mentioned machines and another storage means for storing data other than the above-mentioned common backup data, the data also forming a group of data or groups of data for the above-mentioned machines.
Further, the present invention comprises means for storing the common backup data forming a group of data or a plurality of groups of data for the above-mentioned machines, i.e., a storage means for storing the common backup data, and a storage means for storing information showing that which group of data contained in the common data storage means are contained in the backup data for the above-mentioned machines, that is, a data owner information storage means.
Further, the present invention comprises a take-out function of taking-out a group of data or a plurality of groups of data, for respective machines, which are stored in the backup data storage means.
Further, the present invention comprises means for storing the backup data, that is, a server, and another means having a function of exchanging information with the server, that is, a client.
Further, according to the present invention pieces of attributive information of data such as a data name, a data size or a renewal date of data are exchanged between the client and the server.
Further, in the present invention, data which is required to be transferred from the client to the server is decided based on the attributive information of data exchanged between the client and the server.
Further, in the present invention, the check codes which can be obtained by the calculation from the contents of data such as a cyclic redundancy check or checksum are exchanged between the client and the server.
Further, in the present invention, data which is required to be transferred from the client to the server is decided based on the check codes exchanged between the client and the server.
Further, in the present invention, information is transferred from the server to the client by a different means from the transfer means with which information is transferred from the client to the server.
Further, in the present invention, a storage medium is used as an information transfer means from the server to the client.
Further, in the present invention, a communication means which is suitable for the transmission of a large capacity of data is used as an information transfer means from the server to the client.